Rotary engine



April 21, 1925. 1,534,182

.1. LITHGOE ROTARY ENGINE Filed Jun 19 192;

Patented Apr. 21 1925.

' UNITED. STATES; PATENT oerica.

JOHN LI'IHGOE, or WAKEFIELD, ENGLAND, ASSIGNQR To DIAMOND- COAL CUTTER COMPANY LIMITED, or WAKEFIELD, Yonx, ENGLAND, A BRITISH oo rANY.

J ROTARY nNeiNn Application filed June 19, 1923. Serial No.i846,423.

To all whom it may concern:

Be it known that I, JOHN LITHGOE, a subject of the King of Great Britain, residing at Rawnsclifi'e, \Vakefield, in the county of York, England, have invented certain new and useful Improvements in or Relating to Rotary Engines, of which the following is a specification.

This invention relates to rotary engines of the type in which intermeshing toothed rotors having helically formed intermeshing blades or teeth are employed, as described in the specification of the Van Deventer British Patent No. 12623 of 1911, the chief object of the present invention being to reduce losses of motive fluid which occur in engines of this type due to the clearance between the rotors and the casing and also to avoid any risk of sparking which may occur if the rotors touch any part of the iron casing, such sparking being dangerous where the engine is used in mines for coal cutting or other purposes.

According to this invention there is provided a lining in the rotor casing or cylinder, of an anti-friction non-abrasive material arranged in the form of parallel strips following the lines of the helical rotor blades. These strips are separated by ribs of the casing metal, which lie slightly back of the lining strips. As arranged, for example, in an engine of the kind described in the prior British specification No. 12623 of 1911, where each rotor has a pair of oppositely directed helical blades to ive longitudinal balance, the Working flu1d expanding from the central inlet towards both ends of the rotors, the lining strips form triangles of increasing size but having the same base, the larger triangles successively enclosing the smaller triangles.

In order that the said invention may be clearly understood and readily carried into effect, the same will now be described more fully with reference to the accompanying drawings, in which f/ Figure 1 is a view in cross-section of the principal parts of an engine of the type to which this invention relates.

Figure 2 is a view, partially in plan and Figure 3 is a section through part of the casing taken along a strip of anti-friction lining.

Figure 4 is a development of part-of the surface, showing the triangular arrangement of the'lining strips and the contact faces of the rotor blades; and

Figure 5 is a detail section throughsome of the rotor blades and the lining and casmg. A is the casing, comprising as usual in this class of engine two part cylindrical portions meeting along an apex line a, which apex line is the upper line in the developed surface View, Figure 3. B, B are the antifriction metal lining strips following the lines of the contacting spiral blades C the contacting surfaces 6 of which move parallel to the strips B and are shown in broken 3 lines in Figure 4:. At the apex the strips B are joined together by the horizontal linwith the lining strips and as they pass over the gaps a momentary communication is effected between the expansion chambers 0 formed between the blades, allowing of'a certain amount of feeding of the motive fluid from one chamber to the next. The feeding of fluid in the case of air engines from one chamberto the preceding one prevents excessive cooling due to the expansion of the fluid, and therefore tends to prevent freezing of any moisture that may be present. It also increases the power of the en gine, both with air and steam engines.

The lining is preferably moulded Within the casing and is held in dovetailed recesses, the strips being separately fixed or formed by milling or other process.- The recesses are formed in the inner face of the casing on either side of the apex line a along which the two cylinders of the casing intersect and the lining strips are preferably continuous with-the base 6, which lies along the apex line. The lining is required in the Van Deventer engine only at the lower side of the casing, the upper side of the rotors being open to the exhaust chamber. The inlet port a is shown at the middle of the casing, where the two blade spirals meet.

The ends of the casing A are also provided with soft linings a (Figure 2) Wl'llOh make contact with the ends of the rotor blades and prevent dangerous sparking which might otherwise result from contact between the rotor and the casing.

The composition of the metal employed for 'the lining would depend to some extent on the type of engine, but ordinary white metal is suitable for an air engine or a steam engine where the temperature .is not too material arranged in the form of parallel strips following the lines of the helical rotor blades.

2. In a rotary engine of the kind set forth having rotors with intermeshing helical blades, a rotorcasin and a lining in the said casing of anti-friction non-abrasive material arranged in the form f parallel strips following the lines of the helical rotor blades, the said strips being separated by gaps slightly wider than the contacting faces of the helical blades.

3. In a rotary engine of the kind set forth having rotors with intermeshing helical blades, a rotor casing and a lining in the 7 said casing of anti-friction non-abrasive material arranged in the form of parallel strips following the lines of the helical rotor blades, the said parallel strips meeting to form triangles of increasing size and having a connecting strip forming a common base to all of the said'triangles.

' JOHN LITHGOE. 

